Rainbowfish - Turquoise/Lake Kutubu (Melanotaenia lacustris)

The Lacustris Rainbow is a beautiful fish with an endearing personality. They are one of the larger rainbow fish, reaching about 12.5 cm in length. They have constantly changing but always beautiful colours. Pairing these vibrant colors with an endearing personality makes the Lake Kutubu Rainbowfish one of the most amazing freshwater fish in the hobby.

The Lacustris Rainbow is found only in Lake Kutubu and its outlet in southern Papua New Guinea situated in the Southern Highlands. Lake Kutubu was formed in a depression at 328 ft in the interior of the mountains and is the largest lake in Papua, New Guinea.

The water in that region is very clear and mostly fed from underground springs. Because it is supplied from underground and there is limestone the water passes through, it is alkaline and the pH is around 8.5-9. The lake is heavily populated with plants that can with stand these conditions. These Rainbowfish are omnivorous, feeding on small crustaceans, insect larvae, and algae.

The Lacustris Rainbow are not very difficult to keep, however they like most rainbow fish they are very sensitive to water condition changes. But this can be taken care of with a good filtration system, diligence with water changes, and water testing. If the basic needs of these fish are met, they will easily thrive.

Getting their natural colouring to pop out is sometimes difficult in aquariums but not impossible. To get colours to their full potential the water must be pristine, and there needs to be a proper ratio of males to females. They are generally not picky eaters and will eat a variety of foods, but take caution not to overfeed.

The Lacustris Rainbow can adapt to life in a larger fish community aquarium, but is does exceptionally well in the geographical tank stocked with other rainbow fish. They should always be mixed with fish of a similar temperament and size range. These fish are by nature playful and boisterous. These behaviors can easily turn into violence and aggression with poorly chosen tank mates. These fish get larger then some community fish and their schooling movements can easily stress out other tank mates.

As they are schooling fish, the ratio of males to females is very important to keep a reasonable peace among them. Although you can always keep single sex schools, you will see significantly better colouration if both genders are in the tank.

• Species – Melanotaenia lacustris
• Common Name – Lacustris Rainbow
• Origin – Lake Kutubu and its outlet in southern Papua New Guinea
• Diet – Omnivorous
• PH Range – 7 – 8.5
• Temperature – Tropical and Coldwater 21°c – 26°c
• Breed Type – Egg Scatterer
• Current Size – approximately 5cm (Grows to approximately 12.5cm)
• Sex – Un-sexed